Welcome to a world where Facebook is no longer the fast-growing new kid on the block, but just another big company where the very most entreprenurial people are either at the top running things, or bolting to do their own startup.

There are all kinds of signs that show how big and successful Facebook has become.

There is the valuation. Starting with Goldman Sachs's offer in January, big institutional investors keep pouring money into the company at ever-higher valuations – $50 billion, then $60 billion, and most recently $65 billion.

There are the user numbers. 650 million people visit Facebook.com each month. Half of them come back every day. 200 million people use Facebook on their phone.

There are the revenues and profits. Facebook is on track to turn in $4 billion revenues this year and net $2 billion profits.

There is headcount. A couple years after cracking 500 employees, Facebook is pushing past 2,000.

But perhaps the best indicator of how established Facebook has become is the number of early employees who have already cashed out their some of their stock and quit to start their own things.

Quora was started by Mark Zuckerberg's one-time best friend

Q&A site Quora is a growing list of questions with thoughtful, interesting answers and a strong social element to it. The company is attracting a lot of hype, and we learned that a Quora investor scoffed at a $1 billion buyout as not being enough.

The guy behind Asana built Facebook the company

Asana is a company focused on developing new collaboration software for businesses. Co-founder Dustin Moskovitz gave a brief public demonstration last month and it's on video here.

Ex-Facebookers involved: Dustin Moskovitz, Justin Rosenstein. Moskovitz went to Harvard with Mark Zuckerberg. While Zuck built Facebook the product, Moskovitz organized the collection of people working on the project into an actual company.

Brandee Barker is a coveted PR champ

Brandee Barker joined Facebook way back in 2006. Her first assignment was to deal with press covering the user protests over Facebook's latest feature, the News Feed. The next year, she handled Facebook's Beacon mess.

Now she's launched her own firm, and is already thePR agent to the startup stars, repping white hot startups like Quora and Groupon. Guess Mark Zuckerberg's stamp of approval is a good one to have.

Path goes right after Facebook's bread-and-butter: photo-sharing

Path is a new service that lets you share "moments" (photos) with your 50 closest friends and family members. The site recently raised $8.5 million and has shared over 2 million photos so far.

Jumo is a "social network for do-gooders." The site aims to help you discover what causes are important to you and suggest how to get involved.

Ex-Facebookers involved: Chris Hughes

Cloudera builds software Facebook uses

Cloudera develops and distributes Hadoop, the open source software that powers the data processing engines of the world’s largest and most popular web sites. Experience at Facebook almost certainly played a role in making Hadoop work well.

Ex-Facebookers involved: Jeff Hammerbacher

Storm8 lives away from Facebook, inside Apple's App Store

Storm8 develops mobile games, and its site brags that "each game we released has reached the Top 10 in the App Store free app category."

Ex-Facebookers involved: Perry Tam, Chak Li

Viv is a group-buying startup for the enterprise

Viv is a purchasing club for businesses - they team up to buy large quanitities of products (a focus on eco-friendly) to save money per unit.

Ex-Facebookers involved: Arul Velan

Trialpay feeds off the Facebook games ecosystem

TrialPay is an alternative to traditional e-commerce. Consumers receive a free item from participating merchants simply by completing an offer from a TrialPay advertiser.

Ex-Facebookers involved: Eddie Lim

Daily Strength is a search engine play with some social mixed-in

DailyStrength is a social network that revolves around health - users provide each other with emotional support by discussing their struggles and successes.

Ex-Facebookers involved: Doug Hirsch

i2we will get your Facebook app treated right by Facebook

i2we is a company that offers custom Facebook application development. Shouldn't be too hard when your CEO and founder was its first senior software engineer.

After a stop at Mint.com, Noah Kagan started a company called Gambit

Ex-Facebookers involved: Noah Kagan. There's a "Boycott Facebook until Noah Kagan is re-hired!" group on Facebook. Apparently Kagan was fired for leaking to TechCrunch.

Fwix founder Darian Shirazi met Mark Zuckerberg a week before his High School graduation

Fwix is a location-based service that helps you find interesting things happening nearby. There's a webapp as well as mobile apps for iPad, iPhone, Android, and Palm Pre.

Ex-Facebookers involved: Darian Shirazi. Shirazi met Mark Zuckerberg a week before graduating High School. BusinessWeek says, "He majored in philosophy and worked at Facebook for a year and a half, watching it swell from 15 employees to some 250 employees, before leaving to start his own business."